Apparatus for maintaining a desired speed relation between two shafts



Oct. 29, 1940. WGRAF 2,219,838-

APPARA'IEUS FOR MAINTAINING A DESIRED SPEED RELATION BETWEEN TWO SHAITS Filed Inch 19, 195a j i 6 c Z ll I'nve-nZ'for': WzZZ'er 631/ I 85 chronizing a machine gun to Patented Oct. 29, 1940,

PATENT 'IOFFICE APPARATUS FOR MAINTAINING A DESIRED SPEED RELATION BETWEEN TWO SHAFTS Walter Grai, Berlin-Konradshohe, Germany, assignor to Rheinmetall-Borsig Aktiengesellschaft, Dusseldorf, Germanyna corporation of Germany Application March 19, 1938, Serial No. 197,025 In Germany August 8, 1936 Claims.

The invention relates ,to an apparatus for maintaining a desired speed relationbetween two shafts which comprises a difierential gear which adjusts the brush carrier of .an electric motor movements of a control shaft for-- magnifying the adjusting power of the shaft, which power is only slight, are already known.

According to the invention, the angular move mentofthe planet carrier of a differential gear which causes the displacement of the brushes of the electric motor, said movement being dependent upon the change in speed of the control shaft, is utilised for initiating further control operations which are dependent on the alterations in the speed of the control shaft. Thus,

for example, the displacement of the planet carrier when the speed of the control shaft changes, may be employed in a particularly simple manner'to adjust the moment of firing of a gun which fires through the area swept by'anair-screw.

The invention can also be applied in all other arrangements, in which an operation is produced in dependence on the variable speed of a control shaft, utilizing the angular displacement of a planet wheel carrier.

The accompanying drawing shows an example of a control device constructed in accordance with the invention and showing a side view with certain parts in section of the device for synfire between the blades of a propeller. I I v A control shaft a driven by the airscrew shaft :1: carries a bevel wheel 0 which, together with bevel wheels d and e and a device 3 which com- 40 prises a planet carrier and the brush carrier of an electric motor M, forms a differential gear. When the spindle b of the motor M runs at the same speed but in reverse direction to that of stationary. When, however, the speed ofthe shaft a differs from that of the spindle b, the planet wheel 11 with the device f will revolve about the shaft b. in one direction or the other.

The brushes g of the motor M are thereby moved about the commutator h and thereby change the speed of the motor M until identity of the speeds of the shaft 11 and spindle in has been re-established. The device 1 remains in the new position corresponding to the changed speed. Thus the shaft a, then the planet carrier f remains its relative position is an indication of the speed at the moment. 1

Teeth on the device 1 mesh with those on a gear wheel i which wheel together with the toothed wheels u, we forms a second differential gear which is driven synchronously by the airscrew shaft :1: by way of the shaft w. The drive to the wheel 1: is effected through the shaft 1' which carries a cam 11 which co-operates with a cam followers, and'thus acts on the trigger of m a 'gun by way of a ,Bowden cable t. Movement of. the device f produces a movement of the wheel 1', a and, therefore, an angular displacement between the shafts w and r, the result of which is to effect a. change of the moment of firing the gun 15 p in relation to. the position of the airscrew.

Instead of the differential gear 2', u, v, 2 there may, of course, be used other known means, in order to utilise the displacement of the device 1 so as to change the moment of firing.

The invention can, of course,-also be used for other control operations rendered dependent upon an adjustment of the device f corresponding to the speed of the shaft a, for example for the automatic adjustment of correction in sightg5 ing, in that variations of the position of thedevice 1 which is dependent upon the speed of a laying shaft corresponding to the control shaft,

a, are transmittedto an automatic sighting device by way of a mechanism 2 in dependence on 30 the velocity of a target which is being followed by a gunner.

Having now particularly described and ascertained the nature of my said invention. and in what manner the same is to be performed, I de- 35 clare that what I claim is:

1. Mechanism for synchronizing the rotation of a variable speed control shaft with that of an operating shaft, comprising differential gear driven by the control shaft, said gear including a o planet wheel and carrier therefor, an electric motor having a shaft in driving connection with said differential gear, speed-regulating brushshifting means for said motor movable by said planet wheel carrier to maintain said motor shaft 45 in synchronism with said. control shaft, and means for transmitting the regulating move- -ments of said brush shifting means to the oper-v ating shaft. V 2. Mechanism for synchronizing the rotation of a propeller shaft with that of a shaft for timing the firing of a machine gun through the propeller comprising, differential gear driven by the propeller shaft, said gear including -a planet wheel and carrier therefor, an electric motor 55 having a shaft in driving connection with said differential gear, speed regulating brush-shifting means for said motor movable by said planet wheel carrier to maintain said motor and propeller shafts in synchronism, and means transmitting the regulating movements of said brush shifting means to the timing shaft.

3. Mechanism for synchronizing the rotation of a propeller shaft with thatof a shaft for timing the firing of a machine gun through the propeller comprising, differential gear driven by the propeller shaft, said gear including a planet wheel and carrier therefor, an electric motor having a shaft in driving connection with said difierential gear, speed regulating brush-shifting means for said motor movable by said planet wheel carrier to maintain said motor and propeller shafts in synchronism, and means transmitting the regulating movements of said brush shifting means to the timing shaft, said transmitting means including a second differential gear coupled to said propeller shaft and said timing shaft and having a planet wheel carrier in gear with the planet wheel carrier of the first differential gear.

4. Mechanism for synchronizing the rotation of a variable speed control shaft with that of an operating shaft, comprising difierential gear driven by the control shaft, said gear including a planet wheel and carrier therefor, an electric motor having a shaft in driving connection wi said differential gear, speed regulating brushshifting means for said motor movable by said planet wheel carrier to maintain said motor shaft in synchronism with said control shaft, and means for transmitting the regulating movements of said brush shifting means to the operating shaft, said transmitting means including a second differential gear coupled to said control and operating shafts and having aplanet wheel carrier in gear with the planet wheel carrier of the first differential gear.

5. Mechanism for timing the firing of a machine gun through the path of rotation of a propeller comprising, a shaft driven by the propeller, an electric motor having a shaft, a differential gear set having grear wheelscoupled to the propeller and motor shafts and a planet wheel gear and carrier, speed regulating brush-shifting means adapted to maintain said propeller and motor shafts at equal revolutionary speeds said brush shifting means being angularly movable by said planet wheel carrier, a shaft operating means for firing the machine gun, and asecond I differential gear set having gear wheels coupled to said propeller and firing shafts and a planet gear and carrier in mesh with the planet wheel carrier of the first differential gear set.

WALTER GRAF. 

